William Bryan is the name of the following people:

• William Alanson Bryan (1875–1942), American zoologist, ornithologist, naturalist and museum director
• William C. Bryan (1852–1933), United States Army soldier and Medal of Honor recipient
• William E. Bryan Jr. (1921–2008), United States Air Force major general and flying ace
• William James Bryan (1876–1908), U.S. Senator from Florida
• William Jennings Bryan (1860–1925), orator and three-time Democratic nominee for U.S. President
• William Joel Bryan (1815–1903), Texas soldier and land owner, namesake of Bryan, Texas
• William Joseph Bryan (1926–1977), American hypnotist
• William Lowe Bryan (1860–1955), 10th president of Indiana University
• William Bryan (cricketer) (1856–1933), English cricketer
• William Bryan (North Carolina politician) (1725–1781), American militia general and politician
• Billy Bryan (born 1955), American football player
• Billy Bryan (baseball) (born 1938), American former Major League Baseball catcher
• William "Roddie" Bryan (born 1969), American convicted for the murder of Ahmaud Arbery

• William Brien (disambiguation)
• William O'Bryan (1778–1868), founder of the Bible Christians
• William Bryant (disambiguation)